B48-31 Seizures in the Shadows: Unmasking Nmosd Behind Status Epilepticus

Introduction Neuromyelitis optica spectrum disorder (NMOSD) is an astrocytopathy characterized by aquaporin-4 (AQP4) autoantibodies and typically presents with optic neuritis or longitudinally extensive transverse myelitis. Seizures and brainstem-predominant presentations are uncommon and can be confounded by coexisting autoimmune disease such as sarcoidosis. We report AQP4-positive NMOSD presenting with focal status epilepticus in a patient with biopsy-proven sarcoidosis. Case Description A 58-year-old woman with hepatic and ocular sarcoidosis, prior ischemic stroke with residual deficits, seizure disorder, and lupus anticoagulant positivity was found unresponsive with vomiting and convulsions. She required intubation for airway protection and ICU admission. CT and CTA showed no large vessel occlusion. Initial MRI demonstrated a new medullary T2 and diffusion-restricted lesion, followed by non-enhancing longitudinally extensive T2 signal from the lower medulla through C2 to C6 and into the proximal thoracic cord at T4 to T6. Continuous EEG revealed right occipital lateralized periodic discharges with focal status epilepticus, later improving to diffuse slowing. CSF showed 7 WBC per microliter with 94 percent lymphocytes, protein 63.3 mg/dL, glucose 60 mg/dL. Cultures, viral PCRs, VDRL, cryptococcal antigen, and a paraneoplastic panel were negative. CSF ACE was normal. Serum AQP4-IgG returned positive at 1:1000 by cell-based assay. Given her sarcoidosis, neurosarcoidosis was considered; however, the imaging pattern with medullary involvement and longitudinal cord lesions, the CSF profile, and high-titer AQP4-IgG supported NMOSD. She received methylprednisolone 1 g IV daily for 5 days followed by a prednisone taper and 5 sessions of plasmapheresis, with marked clinical and electrographic improvement and successful extubation. Maintenance ravulizumab was planned thereafter. Discussion This case highlights a rare ICU presentation of NMOSD as focal status epilepticus associated with medullary and longitudinal cervical cord lesions in a patient with established sarcoidosis. Overlap with neurosarcoidosis can delay diagnosis; targeted serology with AQP4-IgG is decisive. Early high-dose corticosteroids and plasma exchange in severe attacks can be organ and life-saving, even when initial suspicion favors alternative autoimmune etiologies. Intensivists should include NMOSD in the differential for refractory seizures or unexplained medullary and cervical cord lesions, including in patients with pre-existing sarcoidosis. This abstract is funded by: None